The invention relates to devices for conditioning air using gas-liquid contact pads, such as precoolers, evaporative coolers, humidifiers, and the like.
In the noted applications, there is a need for saving water. The water distribution system operates best with high line pressure. Also, at high ambient temperatures more water should flow to the pad than at low temperatures. There is further a need for water volume adjustment according to differing pad sizes.
The present invention utilizes variable cycle moisturizing of the pad by the intermittent flow of water or other liquid thereto. The circuit has a first disabled mode, below a given temperature, blocking water flow to the pad. The circuit has a second enabled mode, above the given temperature, providing the variable cycle moisturizing, with cyclic intermittent ON and OFF states of water flow.
Once in the enabled Intermittent mode, the control circuit is further responsive to changing temperature to vary the intermittent flow by changing the relative timing of the ON and OFF timed intervals such that the duration of one increases relative to the other in response to changing temperature above the noted given temperature. This provides automatic temperature responsive adjustment of cumulative water volume while in the variable cycle moisturizing mode.
The control circuit further enables the user to manually preadjust the initial relative timing of the intervals according to pad size, to afford a relatively longer ON interval for larger pads. This enables the same circuit to be used with different size pads, thus affording a universal control circuit for a plurality of different pad sizes. The circuit can be easily customized by the user for his particular pad size, preferably by cutting or not cutting one or more wires according to programmed user instructions keyed to pad size.